The catalytic oxidation performance of toluene over the MnOx catalysts: Effect of MnSO4 content

Abstract

A series of MnOx catalysts with different content of MnSO4 were prepared by hydrothermal method and used for the catalytic oxidation of toluene. The MnOx (Cat-4) showed the best catalytic activity when the MnSO4 content was 0.8 g, and the toluene conversion rate reached 90% at 260°C. Cat-4 catalyst showed more Mn3+ and Oads concentrations, which provided more oxygen vacancies and accelerated the migration rate of oxygen species, and then enhanced the redox performance, resulting in the improvement of the catalytic activity, which depended on the content of MnSO4 over Cat-4. The 100 h stability test showed that the Cat-4 catalyst presented superb stability and water resistance. Furthermore, the oxidation process of toluene was inferred from the in situ DRIFT result: toluene → benzyl alcohol → benzaldehyde → benzoic acid → maleic anhydride → CO2 and H2O.